public class Example4_20 {
  public static void main(String args[]) {
   char a[] = {'a','b','c','D','E','F'};
   for(int i = 0;i<a.length;i++) {
    if(Character.isLowerCase(a[i]))
     a[i] = Character.toUpperCase(a[i]);
    else if(Character.isUpperCase(a[i]))
     a[i] = Character.toLowerCase(a[i]);
   }  
   for(int i=0;i<a.length;i++)
     System.out.println(" "+a[i]);
  }
}
